Transition metal silicides are a class of semiconductor refractory materials. They are most commonly used by the microelectronics industry to fabricate silicon integrated circuits. These materials have recently found much broader applications owing to their electrical conductivity, general chemical inertness, and low work function. For instance, in nanostructure form, transition metal silicides are considered promising candidates to serve as building blocks in the construction of electronic and electrochemical component parts in which dimensional size reductions are constantly sought that preserve certain performance characteristics (i.e., current density, charge/discharge capacity, energy density).
Nanowires fabricated from a transition metal silicide have recently been the subject of much research. A variety of transition metal silicide nanowires have been developed including those with Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Au, Pt, Er, or Ta serving as the transition metal constituent. But the techniques used to make these various nanowires have not been able to reliably, controllably, and precisely fabricate the nanowires in a way that makes their incorporation into electronic devices and electrochemical cells a viable option.
Nanowires comprised of titanium silicide or tungsten silicide are especially intriguing prospects for a wide variety of applications due to their relatively high electrical conductivity, excellent chemical and thermal stability, and corrosion resistance. Their very small size and general physical properties make them particularly attractive for select purposes in electrochemical cells that are used to power automobiles, consumer electronics, and other mobile or stationary devices. A network or collection of many individual electrically conductive microfibers each having a relatively dense circumferential arrangement of surface-bound titanium silicide- or tungsten silicide-based nanowires may, for example, be substituted for finely divided carbon or graphite particles that are commonly dispersed and bound within fuel cell or lithium-ion battery electrode layers. Other applications in electronics (e.g., field emission devices), optoelectronics (e.g., light emitting diodes), photovoltaics (e.g., solor energy devices), and electrochemical devices (e.g., supercapacitors and emitters) may also suit such electrically conductive microfiber collections in some way or another.
But, like the other nanowire forms, a suitable method that can produce a relatively dense quantity of spatially arranged titanium silicide- or tungsten silicide-based nanowires on a microfiber support has not previously been developed. Methods of reliably and controllably growing spatially arranged titanium silicide- and tungsten silicide-based nanowires on the surface of electrically conductive microfibers are therefore needed to further develop the realm of practical applications for these types of metal silicide nanowires.